Premises power source accessory panel for an outdoor unit and method of adapting an outdoor unit with the same

ABSTRACT

An outdoor unit of an HVAC system comprises a frame, at least one refrigerant coil mounted to the frame, a fan motor, a compressor, a controller, and a premises power source accessory panel. The fan motor is coupled to a fan which drives air through the refrigerant coil. The compressor is coupled to the refrigerant coil to drive refrigerant therethrough. The controller is coupled to the fan motor and compressor. The premises power source accessory panel is removably coupled to the frame and includes a bracket and circuit protection element. The bracket has at least one electrical conduit aperture. The circuit protection element is mounted to the bracket and coupleable to a premises power source. The premises power source is a renewable-energy power source located on a premises of the HVAC system. The bracket is removably coupleable to the outdoor unit in lieu of a conventional electrical conduit panel.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Divisional of U.S. Ser. No. 12/975,479 filed onDec. 22, 2010 to Robert B. Uselton, et al. entitled “Premises PowerSource Accessory Panel for an Outdoor Unit and Method of Adapting anOutdoor Unit with the same” currently allowed and commonly assigned withthis application and incorporated herein by reference, which claims thebenefit of U.S. Provisional Application Ser. No. 61/295,941, filed byBrizendine, et al., on Jan. 18, 2010, entitled “Solar Panel,” commonlyassigned with this application and incorporated herein by reference.These applications are also a related to U.S. patent application Ser.No. 12/641,154, filed by Uselton, et al., on Dec. 18, 2009, entitled“Utility-Interactive Inverter System Architecture and Method ofOperation Thereof” also commonly assigned and incorporated herein byreference.

TECHNICAL FIELD

This application is directed, in general, to air conditioning systemsand, more specifically, to a premises power source accessory panel foran outdoor unit and method of adapting an outdoor unit with the same.

BACKGROUND

Mainstream media has extensively covered efforts to reduce reliance onfossil and nuclear fuels in favor of so-called renewable energy, chiefamong these being solar and wind energy. Residential and businesselectric power customers have taken steps to reduce their dependence onthe commercial electric power distribution network (commonly called “thegrid”) and the electric power utilities that sell electric power throughit.

The customers reduce net energy draw not only by reducing consumptionby, for example, increasing thermal insulation, selecting moreenergy-efficient equipment (e.g., appliances) and using it morejudiciously, but also by drawing at least some of the electric powerthey need from renewable-energy power sources, including wind turbinesand photovoltaic (“solar”) panels, they have installed on their ownpremises. Relatively few of these customers derive enough electric powerfrom these premises power sources to go “off the grid.” Instead, mostcustomers remain “on the grid,” using the premises power sources as muchas possible and drawing the remaining electric power they need from thegrid.

Most states have passed laws permitting distributed generation (DG),colloquially known as “grid-tying.” DG is the coupling of premises powersources to the existing power grid such that the sources can synchronizewith, and supply power to, the grid. To compensate customers havingthese sources for the power they provide to the grid, states have alsopassed laws that enable “net-billing” or “net-metering.” Net-billingemploys a second electric meter, separate from the usual one thatmeasures power a customer takes from the grid, that measures the powerthat the customer's premises power sources generate. Net-metering uses asingle, bidirectional electric meter that keeps track of net power flowto or from the grid.

In response to these opportunities, at least one manufacturer ofheating, ventilation and air conditioning (HVAC) systems has begun tointegrate premises power sources into its equipment (e.g., thecondensing, or “outdoor,” units of HVAC or heat pump systems) such thatgrid-tying can occur when the power provided by the sources exceed thatwhich their systems require.

SUMMARY

One aspect provides an outdoor unit of an HVAC system. In oneembodiment, the outdoor unit comprises a frame, at least one refrigerantcoil mounted to the frame, a fan motor, a compressor, a controller, anda premises power source accessory panel. The fan motor is coupled to afan and is configured to drive air through the at least one refrigerantcoil. The compressor is coupled to the at least one refrigerant coil todrive refrigerant therethrough. The controller is coupled to the fanmotor and compressor. The premises power source accessory panel isremovably coupled to the frame and includes a bracket and circuitprotection element. The bracket has at least one electrical conduitaperture. The circuit protection element is mounted to the bracket andcoupleable to a premises power source. The premises power source is arenewable-energy power source located on a premises of the HVAC system.The bracket is removably coupleable to the outdoor unit in lieu of aconventional electrical conduit panel.

Another aspect provides a method of adapting an outdoor unit of an HVACsystem with a premises power source accessory panel. In one embodiment,the method includes selecting a panel appropriate for installation onthe outdoor unit installing the panel on the outdoor unit, andconnecting at least premises power source to the outdoor unit via thepanel if the panel is the premises power source accessory panel. Thepremises power source is a renewable-energy power source located on apremises of the HVAC system. The panel is selected from the groupconsisting of a conventional electrical conduit panel and a premisespower source accessory panel.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference is now made to the following descriptions taken in conjunctionwith the accompanying drawings, in which:

FIG. 1 is a high-level schematic diagram of one embodiment of anelectric power system associated with an example premises and coupled tothe grid;

FIG. 2 is an elevational view of one embodiment of an outdoor unit thatmay be coupled to a premises electric power system;

FIG. 3 is an isometric view of one embodiment of a premises power sourceaccessory panel for an outdoor unit shown with weather-resistant circuitprotection element covers in respective open and closed positions;

FIG. 4 is an isometric view of one embodiment of a portion of theoutdoor unit of FIG. 2 with a conventional panel in place;

FIG. 5 is an isometric view of one embodiment of a portion of theoutdoor unit of FIG. 2 with a one embodiment of a premises power sourceaccessory panel in place in lieu of the conventional panel of FIG. 4;and

FIG. 6 is a flow diagram of one embodiment of a method of adapting anoutdoor unit with a premises power source accessory panel.

DETAILED DESCRIPTION

As stated above, it is desirable to become “greener” and reduce one'sdependence on the commercial electric power distribution network. It isalso desirable from an economic standpoint to sell excess electricityback to the grid. Further, while some effort has been undertaken tointegrate renewable-energy power sources into HVAC equipment, more workcan be done. Specifically, what is needed is a relativelystraightforward way to integrate premises power sources (which includepremises-located renewable-energy power sources and non-renewable powersources) into HVAC equipment without requiring major modifications tothe equipment. What is further needed is a way to integrate premisespower sources into existing HVAC equipment without having to modify theequipment significantly. What is further needed is a way to integratepremises power sources into already installed HVAC equipment withouthaving to modify the equipment significantly.

Accordingly, various embodiments of a premises power source accessorypanel will be introduced herein. In general, the panel is designed to beused in lieu of a panel that does not accommodate premises power sourcesthereby to integrate renewable-energy power sources and other types ofpremises power sources into HVAC equipment without requiring majormodifications to the equipment. Certain embodiments of the panel aredesigned to replace an existing panel that does not accommodate premisespower sources thereby to integrate renewable-energy power sources andother types of premises power sources into existing HVAC equipment oralready-installed HVAC equipment without having to modify the equipmentsignificantly. Various embodiments of the panel are designed for usewith an outdoor unit of an HVAC system. For the sake of illustration,and not by way of limitation, these embodiments will be described in theenvironment of an electric power system associated with an examplepremises and coupled to the grid. An HVAC system is coupled to theelectric power system; the HVAC system has an outdoor unit with whichvarious embodiments of the panel will be associated.

FIG. 1 is a high-level schematic diagram of one embodiment of anelectric power system associated with an example premises and coupled tothe grid. FIG. 1 shows a premises 100. The premises 100 may be land anda building 110 sitting on the land. The building 110 may be a residence,for example a single-family or multi-family residence, an apartment orcondominium complex, a commune, a subdivision, a gated community, amaster-planned community, a retirement or nursing home or village, atrailer park, a recreational vehicle park or any place where people maylive of any conventional or later-developed type. The building 110 mayalternatively or additionally be a business, for example a standaloneretail or office building, a strip or enclosed mall, a restaurant, afactory, a museum, a warehouse, a hotel, a motel, a resort or a lodge orany place of any other conventional or later-developed type where peoplemay work or play.

A branch 120 of a commercial electric power distribution network 130(commonly known as the “grid”) enters the premises 100 and couples to anelectric power meter 140, illustrated in FIG. 1 as being associated withan outer wall of the building 110. A distribution panel 150 is locatedwithin the building 110 and coupled to the meter 140. Those skilled inthe pertinent art will understand that the meter 140 and thedistribution panel 150 may be located anywhere with respect to thebuilding 110 and, indeed, the premises 100 as a whole.

The distribution panel 150 serves as a hub of a premises electric powersystem. Included in the premises electric power system are severalbranch circuits that FIG. 1 shows as extending from the distributionpanel 150 and around the building 110 and the premises 100. For example,a nondedicated branch circuit 160 a extends to a plurality ofunreferenced loads (e.g., outlets or lights), indicated by a pluralityof unreferenced lines) and a first piece of electrically poweredequipment 170 a. A dedicated branch circuit 160 b extends to a singleload, i.e., a second piece of electrically powered equipment 170 b. Adedicated branch circuit 160 c extends to another single load, i.e., anoutdoor unit 170 c that forms at least part of an air conditioningsystem or a heat pump climate control system. For purposes of thisdescription, a dedicated branch circuit is a branch circuit that extendsand provides power to a single load, and a nondedicated branch circuitis designed to provide power to more than one load, even though no loadsor one load may be coupled to it at certain times. Those skilled in thepertinent art are also aware that outdoor units (which are often locatedon the ground adjacent to, or the rooftop of, a building) are employedto exchange heat between a closed-circuit coolant loop and the ambientenvironment to heat or cool coolant flowing through (e.g.,hydrofluorocarbon fluid) in the coolant loop.

For purposes of this description, electrically powered equipment is anelectrical load of any type, including resistive and reactive loads, andincludes all manner of equipment and appliances that may be electricallypowered. Specific examples given herein subsume all manner of climatecontrol equipment, including HVAC equipment, heat pump equipment,desiccating equipment and evaporative cooling equipment. However, thoseskilled in the pertinent art will understand that the teachings hereinapply to all manner of electrical load without limitation.

A bus 190 electrically couples a premises power source 180 to theoutdoor unit 170 c. The premises power source 180 may be any source ofelectrical power (e.g., a wind turbine, a photovoltaic cell, panel orarray, a fuel cell, a battery, a geothermal generator, a hydroelectricgenerator or any other conventional or later-developed or discoveredelectrical power source) that is located on the premises 100. Thepremises power source 180 may produce DC or AC power. Accordingly, thebus 190 may be a DC bus or an AC bus of any appropriate voltage orcurrent capacity. In alternative embodiments, the premises power source180 produces AC power, produces DC power but then converts the DC powerto AC power before transmitting the power along the bus 190 or producesand transmits DC power along the bus 190 for conversion at anintermediate location or a distal end of the bus 190 (the end proximatethe outdoor unit 170 c or, in alternative embodiments, the first orsecond pieces of electrically powered equipment 170 a, 170 b).

Two general embodiments will now be described. In a first embodiment,equipment can use power from two sources: AC power from the electricutility and renewable power from solar photovoltaic modules (“solarpanels”). As will be shown, a utility-interactive inverter becomes thebridge for conversion of DC power (from a premises power source) to ACpower used by, for example, a compressor, fan motor or other loads inequipment. The output side of the utility-interactive inverter isconnected to the “line” side of the equipment contactor (e.g., powerrelay). A “circuit protection element,” such as a circuit breaker, fuse,isolator, suppressor or any other passive or active conventional orlater-developed element, typically interposes the inverter and theequipment contactor. Thus connected, the utility-interactive invertercan sense the voltage and phase of the utility provided AC power tosynchronize with it. As the compressor or other loads consume power, theamount taken from the electric utility source may then be decreased bythe amount of renewable energy that is produced and converted by theutility-interactive inverter. When the compressor and other loads cycleoff, the utility-interactive inverter is still connected to the electricgrid via the branch circuit of the equipment. The equipment thereforebecomes a generation source for running other loads in the building. Ifthe generation capability of the renewable energy system exceeds theloads in the house or building, the power will be exported out to theutility grid. The power meter on the house or building then “turnsbackwards.”

FIG. 2 is an elevational view of one embodiment of an outdoor unit 200that may be coupled to a premises electric power system (e.g., as theoutdoor unit 170 c of FIG. 1 is coupled to the distribution panel 150 ofFIG. 1). In one embodiment, the outdoor unit 200 is a condensing unit ofan HVAC system. In an alternative embodiment, the outdoor unit 200 ispart of a heat pump system. In one embodiment, the outdoor unit 200 sitson a concrete pad. In an alternative embodiment, the outdoor unit 200sits on a rooftop (a “rooftop unit”).

The outdoor unit 200 includes a frame 210 on which are mounted one ormore unreferenced refrigerant coils. A fan motor (not shown) is coupledto an unreferenced fan to drive air through the one or more refrigerantcoils. A refrigerant compressor or heat pump 220 is coupled to the oneor more refrigerant coils to drive refrigerant therethrough. Acontroller 230 controls the operation of the fan motor, the refrigerantcompressor or heat pump 220 and/or other apparatus.

A premises power source accessory panel 300 is removably coupled to theframe 210. Various embodiments of the panel 300 will now be described inconjunction with FIGS. 3-5.

FIG. 3 is an isometric view of one embodiment of a premises power sourceaccessory panel 300 for an outdoor unit shown with weather-resistantcircuit protection element covers in respective open and closedpositions. The panel 300 includes a bracket 310. In the illustratedembodiment, the bracket 310 is composed predominantly of metal, e.g.,steel. In one specific embodiment, the bracket 310 is formed by stampinga metal sheet. In some alternative embodiments, the bracket 310 iscomposed predominantly of plastic. In the illustrated embodiment, thebracket 310 has one or more tabs 320 a, 320 b. If present, the tabs 320a, 320 b are configured to engage corresponding slots on a frame of anoutdoor unit (e.g., the frame 210 of FIG. 2). In such embodiment, thebracket 310 may be installed on the frame by causing the tabs 320 a, 320b to enter and engage the corresponding slots on the frame. Then thebracket 310 may be rotated about an axis defined by the tabs 320 a, 320b until it becomes substantially coplanar with proximate portions of theframe. At this point, one or more fasteners, such as one or more screws,may be employed to affix the bracket 310 to the frame.

In the illustrated embodiment, the bracket 310 serves as a mount for afirst circuit protection element 330 having a weather-resistant cover340 and a second circuit protection element 350. In FIG. 3, the secondcircuit protection element 350 is occluded by its cover. In oneembodiment, the first circuit protection element 330 is configured toprovide both a disconnect function and a fault protection function forthe outdoor unit (e.g., the fan motor and refrigerant compressor or heatpump 220 of FIG. 2). In a related embodiment, the second circuitprotection element 350 is configured to provide a disconnect functionand fault protection for the bus 190 of FIG. 1. Other embodiments haveonly one circuit protection element for the bus 190. Still otherembodiments include other and/or further circuit protection elements forcorresponding other and/or further premises power sources. Suchembodiments can accommodate multiple premises power sources, e.g., oneor more photovoltaic cells and a wind turbine.

The illustrated embodiment of the bracket 310 includes a lateral bracket360 configured to mount a lightning surge arrester. Alternativeembodiments lack the lateral bracket 360.

The illustrated embodiment of the bracket 310 is formed in two sectionswith a joint 370 located therebetween. This allows a section of thebracket 310 that mounts the first and second circuit protection elements330, 350 (an upper section as FIG. 3 illustrates the bracket 310) to besized (e.g., in terms of length and/or width) such that it canaccommodate multiple models and/or sizes of outdoor unit. In colloquialterms, that section may be regarded as being at least somewhat“universal” or “generic,” which generally results in lower overallmanufacturing costs. Consequently, the other section of the bracket (alower section as FIG. 3 illustrates the bracket 310) is sized in termsof its length, width or other configuration such that it accommodatesone or a relatively limited range of models and/or sizes of outdoorunit. In the embodiment of FIG. 3, the lower section of the bracket 310contains, for example, a refrigerant piping aperture 380 located andsized such that a refrigerant pipe can pass through the panel 300 whenit is affixed in place on the frame 210 of FIG. 2. The embodiment ofFIG. 3 is illustrated as including at least one electrical conduitaperture 390 configured to receive an electrical conduit (not shown) forproviding electric power to the outdoor unit from a premises electricpower system. The embodiment of FIG. 3 is illustrated as containingfurther unreferenced apertures, perhaps for electrical or plumbingpurposes or for purposes of mounting one or more further externalcontrols or operational indicators.

FIG. 4 is an isometric view of one embodiment of a portion of theoutdoor unit 200 of FIG. 2 with a conventional electrical conduit panel400 in place. The conventional panel 400 does not always, but insteadonly may, provide an aperture 410 located and sized such that anelectrical conduit 420 can pass through or be terminated in the panel400 when it is installed. The electrical conduit is configured toprovide electric power to the outdoor unit from the grid (not shown).However, the conventional panel 400 lacks circuit protection elementsand any other features that would also allow the panel 400 toaccommodate a premises power source. The conventional panel 400 may alsoprovide an aperture 430 configured to receive a refrigerant pipe 440therethrough.

FIG. 5 is an isometric view of one embodiment of a portion of theoutdoor unit of FIG. 2 with one embodiment of a premises power sourceaccessory panel 300 in place in lieu of the conventional panel of FIG.4. The outdoor unit 200 of FIG. 5 is the same as the outdoor unit 200 ofFIG. 4. FIG. 5 is presented primarily for the purpose of illustratingthat the conventional electrical conduit panel 400 of FIG. 4 may beomitted at the outset, or installed at the outset and later removed,from the outdoor unit 200 and replaced with the premises power sourceaccessory panel 300, thereby initially fitting, or later retrofitting,the outdoor unit 200 to accommodate a premises power source. Thepremises power source accessory panel 300 includes an aperture 410located and sized such that an electrical conduit 420 can pass throughor be terminated in the panel 400 when it is installed. The premisespower source accessory panel 300 also provides a connection to apremises power source. In FIG. 5, this connection is made via a conduit500 leading from the outdoor unit 200 to the premises power source(which FIG. 5 does not show). In the specific embodiment of FIG. 5, thepremises power source is a solar panel. The conventional panel 400 mayalso provide an aperture 430 configured to receive a refrigerant pipe440 therethrough.

FIG. 6 is a flow diagram of one embodiment of a method of adapting anoutdoor unit with a premises power source accessory panel. The methodbegins in a start step 610. In a step 620, an outdoor unit ismanufactured. It is not necessary that the design of the outdoor unit bedependent upon whether or not the outdoor unit is destined to receivepower from a premises power source. Therefore, a single model of outdoorunit can be manufactured to accommodate installation either with orwithout a premises power source. In a step 630, the outdoor unit isinstalled at a particular premises. In a step 640, a panel appropriateto the installation is selected. If the installation is to include apremises power source, a premises power source accessory panel (e.g.,the panel 300 of FIG. 3) may be selected. If the installation is tooperate only off a premises electric power system and is not to have apremises power source, a conventional accessory panel (e.g., the panel400 of FIG. 4) may be selected. Assuming the installation is to includeat least one premises power source, any premises power sources (e.g.,one or more photovoltaic cells, a wind turbine or a standby generator)are installed in a step 650, and, in a step 660, any such premises powersources are connected to the outdoor unit via the premises power sourceaccessory panel. The method ends in an end step 670.

In one embodiment, the step 640 is carried out before the step 630 iscarried out, such that the outdoor unit is shipped to the premises withthe appropriate panel. In another embodiment, the steps 640, 650, 660are carried out a substantial time (e.g., weeks, months or years) afterthe step 630 is carried out, such that an already installed outdoor unitthat has not accommodated a premises power source is thereby retrofittedto accommodate a premises power source.

Those skilled in the art to which this application relates willappreciate that other and further additions, deletions, substitutionsand modifications may be made to the described embodiments.

What is claimed is:
 1. An outdoor unit of an HVAC system, comprising: aframe; at least one refrigerant coil mounted to said frame; a fan motorcoupled to a fan and configured to drive air through said at least onerefrigerant coil; a compressor coupled to said at least one refrigerantcoil to drive refrigerant therethrough; a controller coupled to said fanmotor and said compressor; and a premises power source accessory panelremovably coupled to said frame and including: a bracket having at leastone electrical conduit aperture, and a circuit protection elementmounted to said bracket and coupleable to a premises power source,wherein said premises power source is a renewable-energy power sourcelocated on a premises of said HVAC system, said bracket removablycoupleable to said outdoor unit in lieu of a conventional electricalconduit panel.
 2. The outdoor unit as recited in claim 1 wherein saidoutdoor unit is a condensing unit of said HVAC system and saidcompressor is a refrigerant compressor.
 3. The outdoor unit as recitedin claim 1 wherein said outdoor unit is part of a heat pump system andsaid compressor is a heat pump.
 4. The panel as recited in claim 1wherein said bracket further includes at least one tab configured toengage corresponding slots on said outdoor unit.
 5. The panel as recitedin claim 1 further comprising a circuit protection element mounted tosaid bracket and configured to be coupled to said outdoor unit.
 6. Thepanel as recited in claim 1 wherein said bracket includes a lateralbracket configured to mount a lightning surge arrestor.
 7. The panel asrecited in claim 1 wherein said bracket includes a first section and asecond section coupled thereto by a joint, said first section sized toaccommodate multiple models of said outdoor unit.
 8. The panel asrecited in claim 1 wherein a weather-resistant circuit protectionelement cover is associated with said circuit protection element.
 9. Amethod of adapting an outdoor unit of an HVAC system with a premisespower source accessory panel, comprising: selecting a panel appropriatefor installation on said outdoor unit from the group consisting of: aconventional electrical conduit panel, and a premises power sourceaccessory panel; installing said panel on said outdoor unit; connectingat least one premises power source to said outdoor unit via said panelif said panel is said premises power source accessory panel, whereinsaid premises power source is a renewable-energy power source located ata premises of said HVAC system; and mounting a lightning surge arrestorto a bracket of said premises power source accessory panel.
 10. Themethod as recited in claim 9 further comprising installing said outdoorunit, said installing said outdoor unit being carried out before saidselecting.
 11. The method as recited in claim 9 further comprisinginstalling said outdoor unit, said installing said outdoor unit beingcarried out after said selecting.
 12. The method as recited in claim 9further comprising installing said at least one premises power source.